Notes on GTID related functions after upgrading from 5.6 to 5.7.
Author: Qin Fulang, a member of the DBA team of Aikesheng, responsible for handling daily project problems and troubleshooting company platform problems. A DBA who loves the Internet, knows photography, and knows cooking skills is not a good driver, didi~
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This article has a total of 400 words and is expected to take 2 minutes to read.
background
A financial company has a system that has just been migrated from 5.6 to 5.7.30. GTID was not enabled before the migration, but GTID related functions were enabled after the migration. CREATE TABLE ... SELECT ...When the business uses imported data in the usual way, an error occurs: Error Code:1786 (HY000): Mysql Statement violates GTID consistency: CREATE TABLE ... SELECT.
Problem principle
This problem is relatively simple. The reason is that the migrated MySQL5.7 uses GTID and enables enforce_gtid_consistencyparameters (GTID strong consistency).
To ensure the consistency of distributed transactions, MySQL uses GTID to uniquely identify a transaction. In GTID mode, DDL and DML statements will automatically generate different GTIDs to identify different transaction operations. However, CREATE TABLE ... SELECT ...only one GTID is generated, and DDL and DML operations are merged into one transaction execution. This will cause master-slave data inconsistency when statement execution fails. Turning on enforce_gtid_consistencythe parameter is for the atomicity of GTID transactions.
The official documentation also explains CREATE TABLE ... SELECT ...this operation:
solution
For safety reasons, it is not recommended to turn this parameter off.
On MySQL5.7, you can solve this problem by splitting SQL into two sentences, such as:
#先创建表
CREATE TABLE ... LIKE...
#再插入数据
INSERT INTO ... SELECT ...
Although the previous single SQL can be easily and quickly derived to another table, it can be a little more troublesome for safety.
MySQL 8.0
The good news is that starting from MySQL8.0.21, storage engines that support atomic DDL allow the use of CREATE TABLE ... SELECT ...statements.
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